"

Western Port Bay – a fishing haven
  |  First Published: December 2015



In November 2006, then-Premier Steve Bracks promised to ban commercial netting in Western Port Bay, which would create a recreational fishing haven.

This promise recognised the bay’s popularity among Melbourne anglers and followed the popular closures of commercial fishing in several eastern Victorian inlets. At the time, reported landings from commercial fishing in the bay had fallen from 200 tonnes in the late 1970s to 60 tonnes, worth an estimated $0.3 million. In December 2007, commercial netting in the bay ceased. Apart from a low level of longlining and other hook or jig fishing, the bay effectively became a recreational fishing haven.

In June 2009, Fisheries Victoria held a Western Port Bay fishery assessment workshop in Queenscliff. Fisheries managers, researchers and Fisheries Officers met with experienced anglers, charter operators and commercial fishers to review fisheries trends and assess the current state of key fish stocks and the overall state of the fishery.

The workshop conclusions on the status of major fish stocks were that whiting and calamari have increased in abundance since the mid-1990s and snapper and gummy sharks numbers were also increasing. Combined with fishing elsewhere, recreational fishing for elephant fish in Western Port Bay at recent levels was considered unsustainable and the effectiveness of the lower bag limit was yet to be demonstrated. Anglers at the workshop were generally happy with the state of the fishery and observed that seagrass beds appear to be recovering after substantial losses during the 1970s.

They concluded that, after just 18 net-free months it was too soon to judge the effect of the 2007 closure of commercial netting on recreational fishing participation and catch rates. The plan was that, over the next few years, continued close monitoring of recreational fishing should enable measurement of the expected benefits in terms of fishing participation, catch rates and ‘quality experiences’.

In August 2015, Fisheries Victoria researchers, managers and Fisheries Officers met again with recreational fishers and charter operators to discuss the state of the Western Port Bay fishery and key fish stocks. One of the main aims was to review progress towards total reliance of the bay fisheries assessments on recreational fishing data for the first time. This was reflected in the strong turnout by Angler Diary volunteers, who contribute much of this vital information. Along with charter operators and Fisheries Officers, their input at the meeting helped to clarify recent trends in the fishery and issues requiring management attention.

THE COMMERCIAL FISHERY

The steady decline in commercial catches from the bay since the late 1970s accelerated following the commercial licence buy-outs of the early 2000s. This occurred despite the fact that 42 commercial access licence holders were still entitled to fish there using hooks. In addition there were clear indications that the main target species were abundant. In fact, during the 2000s the overall commercial catch rates increased while the commercial fishing pressure declined. From the initial buy-out in 2000 until netting ceased in 2007, total annual catches averaged 52 tonnes. Since then the annual commercial line-only catches have not exceeded one tonne. Gummy shark has been the main species taken, along with smaller quantities of snapper, whiting, pipis and calamari.

By the December 2007 netting closure, the number of commercial fishing access licences for line fishing in the bay had been whittled down to 42. In practice, most of these commercial fishers continued to operate solely in Port Phillip Bay as they had in the past; most recently, only two fished in Western Port Bay. At this low level of fishing activity their catch records are of no use for fishery assessments. For the first time, these assessments are now totally dependent on recreational fishing data. Fortunately, Fisheries Victoria has been collecting detailed boat ramp survey and Angler Diary monitoring data since 1998.

THE RECREATIONAL FISHERY

After Port Phillip Bay, Western Port Bay is Victoria’s largest recreational fishery. The almost-total removal of commercial fishing has made it a recreational fishing haven. The question is: has it become the bonanza that anglers expected?

Professor Greg Jenkins presented the results of research showing the associations of different fish species with the various habitat types in the bay: two distinct seagrass habitats (Zostera and Halophila), macro-algae-rocky reef habitats and two other distinct algal habitats. His study of 15 years of creel survey data, linked with habitat mapping, provided new insights to fishery assessment and the importance of protecting bay habitats.

Catch estimates from boat ramp surveys and off-site (phone-diary) surveys were presented to describe recreational catches of major species in the bay over time.

Unsurprisingly, given the lack of angler-friendly shore access points, the recreational fishery is 99% boat-based. Most anglers (95%) live in the Metropolitan area and most (96%) fish in this bay at least five times per year, mainly (70%) during summer and autumn.

In keeping with modern approaches to managing fisheries and keeping track of targeted fish stocks, Fisheries Victoria uses a number of performance indicators. These include trends in stock recruitment (ie spawning success), catch rates, length and age composition of catches, targeted fishing effort, angler satisfaction and perceptions regarding the fishery. By examining the latest information across all these measures, anglers at the workshop were able to discuss whether Western Port Bay had become a recreational fishing ‘honey pot’ since 2007.

KING GEORGE WHITING

Whiting spawn in late autumn and winter and larvae enter the bays at around 20-25mm long and 100-130 days old. Greater numbers appear during years of stronger westerly wind patterns and modelling suggests that they originate from near the Victoria/South Australia border.

Whiting may live more than 20 years but the oldest recorded from Victorian waters are aged 11 years. In contrast, whiting of up to 70cm have been aged at 18 years – and in spawning condition – in northern Tasmanian waters. This suggests an alternative theory of the origin of larval whiting that enter eastern inlets such as Corner Inlet. It could even explain inconsistencies between larval recruitment to Western Port Bay compared to Port Phillip Bay. Right now, the uncertain stock structure of whiting is being investigated.

At age four years most sub-adults leave Port Phillip Bay but in Western Port Bay some fish stay a year longer on the Balnarring-Flinders Amphibolis seagrass beds, accounting for the larger sizes caught there. Because whiting are takeable at ages 2-4 years and larval recruitment is so variable, catches ‘bounce around’ showing year-to-year patterns that broadly follow the trend in larval recruitment 2-3 years earlier. The latest recruitment trend suggests that the next peak in catches can be expected in 2016.

Numbers of whiting are caught most consistently during autumn and winter. In most of the 17 years of recreational fishery records, 20% of trips that targeted whiting resulted in catches of 10 or more.

A phone survey of 18 Diary Anglers indicated majority views that numbers of both legal and sub-legal sized whiting were down while most of the legal sized fish were larger than usual. The consensus among anglers at the workshop was that whiting catches in 2015 were the lowest in many years.

While undersized whiting are more prevalent on the fine-leaf Zostera seagrass beds in the southeast part of the bay, legal sized fish are found over shallow seagrass beds where ever they occur around the bay.

SNAPPER

Western Port Bay snapper are part of the western Victorian stock. While Port Phillip Bay is the major spawning and recruitment source for this stock, juveniles and adults move freely into other inlets and coastal waters.

Pinkies begin to mature at around 30cm and most are mature at 40cm and age 6-7 years. Adults of 11kg have been aged at up to 37 years so they have the potential to contribute to the fishery over long periods. Monitoring of spawning success since 1992 has shown above average pulses of recruitment in 2000/01, 2003/04, 2004/05, 2008/09, 2012/13 and 2013/14. As snapper spawned in these pulses take just four years to grow to 28cm, pinkie catch rates can vary significantly at 2-5 year time-scales.

In contrast, it takes snapper around seven years to become adults, so year-to-year variations in catches of larger fish tend to be smoothed out. The impact of occasional exceptional recruitment pulses combined with snappers’ longevity contributes to this evening-out process. Nevertheless, the poor-to-average years of recruitment since the exceptional pulse of 2003/04 have exposed the snapper stock to a ‘mining out’ process by the high recreational fishing intensity in both bays, along with commercial fishing pressure. So, it is not surprising to see that the fisheries for large snapper in the two major bays have shown signs of decline over the past season.

Researchers attending last year’s Ti-Tree Snapper competition measured and aged snapper weighed-in from Western Port Bay. They found the two dominant year classes were from 2000/01 and 2003/04 – the two largest recruitment events in the past 18 years. Again, this illustrates two points: fish from such big events may carry much of the fishery for years to come but eventually fishing pressure will wear them down.

Angler Diary volunteers catch and record details of snapper of all sizes above approximately12cm. Their catch rates of large snapper showed relative stability until a recent decline that provides evidence that the fishery has been eating into that extremely large 2003/04 year class. Anglers and charter operators at the workshop indicated a particularly alarming drop in snapper catches this year – a drop mirrored to a lesser degree in Port Phillip Bay.

On the plus side, Angler Diary records indicate large numbers of small snapper spawned in 2011/12, which was a poor spawning year in Port Phillip Bay. This suggests that there may be some localised recruitment in Western Port Bay. As a result of this recruitment pulse, large numbers of pinkies are expected to enter the fishery over the next 12 months. This will be accompanied by influxes of smaller snapper from above average recruitment in 2012/13 and 2013/14. These undersized fish will pester anglers before making their way into the pinkie fishery from 2017.

Length records indicate that the recreational snapper catch in Western Port Bay is being dominated by 40-60cm and 1-3kg fish.

The study of fish-habitat associations showed consistent patterns with larger snapper being more prevalent in deeper water, particularly in the southwestern part of the bay. Anglers commented that the deeper water of the North Arm and, until the past four years, between Cowes and Rhyll had also been productive. Like whiting, small snapper were mostly associated with shallower habitats in the southeast.

FLATHEAD

The two main species caught by anglers are sand flathead and Yank flathead, with small numbers of rock flathead. It is highly probable that the populations of all three species are independent of those occurring in Port Phillip Bay.

Sand flathead are mature by age five years and 25cm and can live to at least 23 years and reach 50cm. Angler Diary records show that 25-30cm fish dominate anglers’ catches. Yank flathead are mature by age two years and 25cm and can live to at least 12 years and reach 70cm.

Angler catch rates for both of these species vary year by year and show a slowly declining trend over the past 18 years. Numbers are so low that only 5% of trips targeting ‘flathead’ result in catches of five or more and only 2% of trips produce 10 or more. The highest catch rates occur down the western side of the bay and to the north of Phillip Island.

GUMMY SHARKS

Gummy sharks form a single southern Australian stock in which individuals may move over wide distances. They mature at age 6-8 years and may live for at least 16 years with males reaching 150cm and females 180cm. Females mature at 120cm and a large female may produce 40 pups in one season.

Pupping occurs during summer in sheltered shallow waters including Western Port Bay where the main pupping area is in the south east, from Rhyll to Corinella. Seven-gill sharks prey on gummy shark, school shark and elephant fish pups in the bay and are believed to be increasing in numbers.

Unlike whiting, snapper and flathead where recruitment depends critically on variable environmental conditions during and immediately following annual spawning seasons, recruitment of gummy sharks depends principally on the numbers of mature females in the stock. Like other shark species, this feature makes gummy sharks particularly vulnerable to overfishing.

The estimated recreational catch of gummy sharks in 2006 was 15 tonnes – comparable to the highest annual commercial catches from the bay in the previous 30 years. Although success rates vary, on average around 30% of trips targeting gummy sharks result in catches of one or more, mainly from January to May. In recent years, catches have been most consistent off Tooradin and in the southwestern part of the bay.

Although few school sharks are caught there, Western Port Bay is an important nursery area for this species with 1-2 year old juveniles being common.

The main discussion point was whether the legal minimum length for gummy sharks should continue to be expressed as the partial length, 45cm, or changed to the equivalent total length of 70cm. While this was not resolved at the workshop it is an ongoing point of discussion between Fisheries and angler groups.

In next issue of VFM, the second part of the Western Port Bay report looks at the decline in elephant fish numbers, angler satisfaction levels and some pressing management issues. It considers whether this netting-free fishery is living up to anglers’ expectations and what lessons the Government’s ‘Target One Million’ program can apply in Western Port and Port Phillip bays.

Fact Box

King George whiting in Tasmania, Formerly found only around the Furneaux Islands, during the past 10 years whiting have become so abundant off parts of Tasmania’s north and east coasts that catch limits are being planned. As well as being caught in increasing numbers they are commonly taken at much larger sizes and at ages up to 12 years older than in Victorian waters. Off the north west coast and in Georges Bay (St Helens) whiting of up to 70cm have been caught and fish larger than 60cm are not uncommon. A legal minimum size of 35cm is being considered. Sub-adults are found in Georges Bay raising the possibility that whiting may be spawning in Tasmanian waters. If so, this could cast new light on the origins of the King George whiting in Victoria's bays and inlets.

Estimates of recreational catches of major species

Species2000/01 (t)2006/07 (t)2008 (t)
King George whiting6465n/a
Flathead6632n/a
Snapperindeterminate121n/a
Gummy shark 6015n/a
Elephant fish692745
Reads: 1178

Matched Content ... powered by Google